1. Field of the Invention
The present invention relates to compositions of volatile organic compounds with biological activity against plant pathogens, particularly the fungus Ganoderma boninense that is a causative agent of the oil palm disease Ganoderma Basal Stem Rot. The disclosure also provides compositions comprising at least one known pesticidal agent useful for selective pest control applications.
2. Background Information
Oil palm, Elaeis guineensis, is the most important plantation crop in Malaysia. Four tons of palm oil are produced annually per hectare from this crop plant. Many small private landowners are able to profit from the production and sale of the palm oil, making this an activity of great economic importance. Presently, Malaysia's oil palm industry is under threat as it is faced with a very serious plant disease problem. This problem is a prevailing incurable oil palm disease called Ganoderma Basal Stem Rot (BSR) caused by Ganoderma boninense. Presently, BSR is rapidly becoming the major threat to oil palm cultivation and palm oil production in Southeast Asia.
In BSR disease, basal stem rot is only one part of the disease cycle. Ganoderma boninense also causes a seedling disease and an upper stem rot of more developed palms. Spores of G. boninense have multiple roles in the infection process to bring about the three distinct phases of this important plant disease. This pathogenic organism is also prevalent on other major plantation plants including coconut, betel nut, tea, cacao, acacia and poplar.
With no effective cure at present, BSR has a huge economic impact on the Malaysian oil palm industry. Thus, plant health is crucial in obtaining maximal productivity of the oil palm and techniques, methods and management ideas are needed to control BSR. Attempts to control this disease with agrochemicals have not been very successful. This could be due to the fact that the oil palms already possessed latent fungal infections at the time of the chemical treatment. Biological control agents have also been tried against Ganoderma with limited success. Saprophytic organisms (such as Trichoderma harzianum) merely arrest the spread of disease by competing against Ganoderma to reduce its opportunity to colonize oil palm roots.
BSR is a particular concern because the activity of replanting oil palms can accelerate spread of the disease. It is well known that successive replanting of oil palms can be rapidly exploited by soil borne fungi such as Ganoderma. Soils that continuously support the growth of palms eventually act as a reservoir for Ganoderma fruiting structures and spores of this organism. Soils that are replanted with new palms are immediately exposed to a high load of inoculum (spores) and eventually become infected by Ganoderma boninense. 
It is widely believed that the problem of basal stem rot of palm will become increasingly serious as more and more established plantations become due for second or even third replanting. Environmental considerations, coupled with governmental directives, will reduce exploitation of new forest areas, making further replanting of these crops necessary. There is a need for integrated management systems for Ganoderma and related diseases to maintain the success of the oil palm industry.